package org.bcos.web3j.crypto.sm2.crypto;

/**
 * Block cipher engines are expected to conform to this interface.
 */
public interface BlockCipher {
	/**
	 * Initialise the cipher.
	 *
	 * @param forEncryption
	 *            if true the cipher is initialised for encryption, if false for
	 *            decryption.
	 * @param params
	 *            the key and other data required by the cipher.
	 * @exception IllegalArgumentException
	 *                if the params argument is inappropriate.
	 */
	public void init(boolean forEncryption, CipherParameters params)
			throws IllegalArgumentException;

	/**
	 * Return the name of the algorithm the cipher implements.
	 *
	 * @return the name of the algorithm the cipher implements.
	 */
	public String getAlgorithmName();

	/**
	 * Return the block size for this cipher (in bytes).
	 *
	 * @return the block size for this cipher in bytes.
	 */
	public int getBlockSize();

	/**
	 * Process one block of input from the array in and write it to the out
	 * array.
	 *
	 * @param in
	 *            the array containing the input data.
	 * @param inOff
	 *            offset into the in array the data starts at.
	 * @param out
	 *            the array the output data will be copied into.
	 * @param outOff
	 *            the offset into the out array the output will start at.
	 * @exception DataLengthException
	 *                if there isn't enough data in in, or space in out.
	 * @exception IllegalStateException
	 *                if the cipher isn't initialised.
	 * @return the number of bytes processed and produced.
	 */
	public int processBlock(byte[] in, int inOff, byte[] out, int outOff)
			throws DataLengthException, IllegalStateException;

	/**
	 * Reset the cipher. After resetting the cipher is in the same state as it
	 * was after the last init (if there was one).
	 */
	public void reset();
}
